This invention relates to a method and apparatus for compressing foundry sand in a molding space. It also relates to a molding machine equipped with a flask and a pattern carrier, wherein upper and lower mold halves are alternately molded for each empty mold half carried therein. In particular, it relates to improvement in the pattern plate carrier with an auxiliary flask carried along with a pattern plate.
Conventionally, foundry sand has been compressed in a molding space formed between a pattern plate and molding flask by having the pattern plate and compressing means approach each other. This method has some problems in that since it needs large-sized cylinders the height of a molding machine used for them becomes high and the related facilities, such as a pit, cost a lot accordingly. This method has also some disadvantages in that since in it, wherein an auxiliary flask on which a molding flask is put is put on the upper part of a pattern plate, the foundry sand thrown into the molding space to fill it must be smoothed prior to compression, so that a lot of spilled sand may be generated, and so that uneven compression or an uneven compressed surface may occur. Therefore, a lot of time and labor are needed to deal with such disadvantages. Further, in the conventional blow-squeeze machine, wherein foundry sand is blown into a molding space to fill the space defined by squeeze heads, a molding flask on which an auxiliary flask is put, and a pattern plate, the foundry sand is squeeze compressed.
Japanese Patent Early publication No. 63-63552 discloses a pattern plate carrier with an auxiliary flask as an example used in such a blow squeeze machine. In the conventional pattern plate carrier with an auxiliary flask, a pattern plate is mounted on a carrier box disposed movably up and down such that the auxiliary flask is moved up and down through cylinders fixed to the carrier box. Since to move the auxiliary flask of the thus constituted conventional pattern plate carrier large sized air cylinders having a large diameter are used, a great space is needed as well as a large sized, high priced blow squeeze machine. Further, there is also a problem in that to remove the piping of the air cylinder the replacement of the pattern plate carrier with an auxiliary flask is very troublesome.
In view of these circumstances this invention was made. Thus, one object of this invention is to supply a method and apparatus for molding foundry sand into a mold with a given uniform hardness in a molding space defined by a pattern plate and flask members without using a pit or large sized oil cylinders.
Another object of this invention is to supply a molding machine and pattern carrier wherein the generation of spills or scraps of sand is reduced, and wherein foundry sand is homogenously compressed at a low cost.
A further object of this invention is to supply a compact pattern plate carrier with an auxiliary flask that can be easily replaced.
In accordance with one aspect, the method of this invention for molding a mold by compressing foundry sand disposed in a molding space defined by a pattern plate, subsidiary flask, and flask member comprises the steps of throwing foundry sand into the molding space, pressing down the foundry sand in the molding space while at least said subsidiary flask is being kept unable to go downward, and further pressing down the foundry sand in the molding space while both said subsidiary flask and said flask members are being kept unable to go downward.
In accordance with a further aspect, the apparatus of this invention for molding a mold comprises a pattern plate fixedly disposed horizontally, a subsidiary flask disposed around said pattern plate so as to be moved up and down, lift means for moving said subsidiary flask up and down, a flask member disposed above said subsidiary flask so as to be moved up and down, and compressing means disposed above said flask member wherein the ends of the compressing members can reach at least a point within said flask member.
In another aspect, the apparatus of this invention for molding a mold comprises a pattern plate disposed fixedly and horizontally, a subsidiary flask disposed around said pattern plate so as to be moved up and down, lift means for moving said subsidiary flask up and down, a flask member disposed above said subsidiary flask so as to be moved up and down, and compressing means disposed above said flask member, wherein the ends of the compressing members can reach at least a point within said flask member.
In still another aspect, the pattern carrier of this invention comprises a mount on which the pattern plate is mounted and a flask-shaped frame disposed to be movable up and down around said pattern plate for removing a finished mold.
In a further aspect, the pattern carrier of this invention comprises a mount on which a pattern plate is mounted, a flask-shaped frame disposed to be movable up and down around said pattern plate for removing a finished mold, a plurality of guide pins for moving said flask-shaped frame up in a parallel manner, and a plurality of actuators mounted on a molding.
In a still further aspect, the pattern plate carrier of this invention for carrying a pattern plate comprises a plurality of upwardly movable cylinders mounted on said pattern plate carrier to move said auxiliary flask, at least two special oil cylinders mounted on said pattern plate carrier for supplying fluid to the upward cylinders by being alternately contracted, and at least two cylinders disposed separately outside said pattern plate carrier and constituted such that the alternate expansion of said at least two cylinders causes said special oil cylinders to alternately contract.